纤维素纳米晶体对壳聚糖纺丝原液流变行为的影响

首先将纤维素纳米晶体(CNC)悬浮液进行超声分散,然后与壳聚糖乙酸溶液进行高速搅拌共混,制备不同CNC含量的壳聚糖-CNC共混均匀溶液。采用平板式旋转流变仪研究了CNC含量对壳聚糖溶液流变行为的影响。测试结果表明:壳聚糖-CNC共混溶液表现为非牛顿流体行为;黏度随温度的上升而下降,但在高剪切速率范围内,温度对黏度的影响不再明显;随着CNC含量的增加,壳聚糖溶液的表观黏度增大,对剪切速率的敏感性增强,同时非牛顿指数和黏流活化能降低;共混原液的结构黏度指数随CNC含量减少以及温度升高而降低;壳聚糖-CNC共混溶液储能模量和损耗模量的交叉点随温度的升高向高频区移动,随CNC含量的增加向低频区移动,溶液流变规律基本符合Cox-Merz规则。

The Influence of Cellulose Nanocrystal on the Rheological Behavior of Chitosan Spinning Dope

First, suspension of cellulose nanocrystal(CNC) was prepared by ultrasonic dispersion, and thenchitosan-CNC blend solutions of different CNC contents were prepared with acetic acid solution of chitosanby high-speed mixing blend. The influences of CNC content on the rheological behavior of chitosan solutionwere investigated by the plate rotational rheometer. The test results showed that the chitosan-CNC blendsolution showed non- Newtonian behavior. The viscosity decreased when the temperature rised, but theinfluence on the viscosity was no significant in the high shear rate range. The apparent viscosity of chitosansolution increased with the increase of CNC content, and the sensitivity was enhanced to shear rate, also thenon-Newtonian index and viscous flow activation energy of chitosan solution decreased with the increase ofCNC content. The structural viscosity index of the blend solution decreased with CNC content decreasingand temperature increasing. The cross points of the storage modulus and the loss modulus of chitosan-CNCblend solution were moved to the high frequency region with the increase of temperature and were moved tothe low frequency region with the increase of CNC content. The rheological behavior of the solution wasbasically in accordance with the rules of Cox-Merz.